1. Navy docs deploy on ships. In fact, if you are FP or IM you may be permanently (e.g., 3yrs) assigned as a SMO to a carrier or gator.
2. If you have the urge to deploy on a small boy (e.g., FFG, DDG, or CG) there are those opportunities too. I forget what it was called (fleet surgical team?), but a surgeon friend of mine deployed 3mo on a CG as part of a CJTF.
3. If you want close to the action, you can do that to. Forward surgical teams have ortho, gen surg, anesthesia, and IM. My understanding is they get to deploy fairly far forward to all the wonderful AORs where a surgeon might be needed.
4. If you want to do humanitarian stuff, you can do that too. I don't know anyone who volunteered to go to Haiti that was turned down.
5. If you want to be in the Army, you can do that. I don't know how many, but the Navy has many medical personnel deployed as IAs in support of the Army.
6. If you want to be (like) a Marine, you can do that.
So their are a plethora of opportunities are out there on ships and off. the problem is many docs try to get out of them for various reasons (family, tired from past deployments, fear, etc.). You will PROBABLY be made to do a deployment(s) if you stay in long enough (and want to get promoted).